Observations over the last decade have revealed exoplanetary systems that are completely different from our own Solar System. These extreme planetary systems are changing our view of planetary formation. I will focus on hot Jupiters, giant planets in close orbits around their host stars (period about 5 days). Many hot Jupiter systems are found to have highly misaligned orbital axes relative to the stellar spin axes. I will discuss possible physical causes behind the misalignment, including the roles of star-disk-binary interactions, resonances and spin chaos. I will also discuss the dynamics of planets around compact stellar binaries.